/***************************************************************************************[SolverTypes.h]
 Glucose -- Copyright (c) 2009-2014, Gilles Audemard, Laurent Simon
								CRIL - Univ. Artois, France
								LRI  - Univ. Paris Sud, France (2009-2013)
								Labri - Univ. Bordeaux, France

 Syrup (Glucose Parallel) -- Copyright (c) 2013-2014, Gilles Audemard, Laurent Simon
								CRIL - Univ. Artois, France
								Labri - Univ. Bordeaux, France

Glucose sources are based on MiniSat (see below MiniSat copyrights). Permissions and copyrights of
Glucose (sources until 2013, Glucose 3.0, single core) are exactly the same as Minisat on which it
is based on. (see below).

Glucose-Syrup sources are based on another copyright. Permissions and copyrights for the parallel
version of Glucose-Syrup (the "Software") are granted, free of charge, to deal with the Software
without restriction, including the rights to use, copy, modify, merge, publish, distribute,
sublicence, and/or sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

- The above and below copyrights notices and this permission notice shall be included in all
copies or substantial portions of the Software;
- The parallel version of Glucose (all files modified since Glucose 3.0 releases, 2013) cannot
be used in any competitive event (sat competitions/evaluations) without the express permission of
the authors (Gilles Audemard / Laurent Simon). This is also the case for any competitive event
using Glucose Parallel as an embedded SAT engine (single core or not).


--------------- Original Minisat Copyrights

Copyright (c) 2003-2006, Niklas Een, Niklas Sorensson
Copyright (c) 2007-2010, Niklas Sorensson

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 **************************************************************************************************/

#ifndef Glucose_SolverTypes_h
#define Glucose_SolverTypes_h

#include <assert.h>
#include <pthread.h>
#include <stdint.h>

#include "mtl/Alg.h"
#include "mtl/Alloc.h"
#include "mtl/IntTypes.h"
#include "mtl/Map.h"
#include "mtl/Vec.h"

namespace Glucose {

//=================================================================================================
// Variables, literals, lifted booleans, clauses:

// NOTE! Variables are just integers. No abstraction here. They should be chosen from 0..N,
// so that they can be used as array indices.

typedef int Var;
#define var_Undef (-1)

struct Lit
{
	int x;

	// Use this as a constructor:
	friend Lit mkLit(Var var, bool sign);

	bool operator==(Lit p) const { return x == p.x; }
	bool operator!=(Lit p) const { return x != p.x; }
	bool operator<(Lit p) const { return x < p.x; } // '<' makes p, ~p adjacent in the ordering.
};

inline Lit
mkLit(Var var, bool sign = false)
{
	Lit p;
	p.x = var + var + (int)sign;
	return p;
}
inline Lit
operator~(Lit p)
{
	Lit q;
	q.x = p.x ^ 1;
	return q;
}
inline Lit
operator^(Lit p, bool b)
{
	Lit q;
	q.x = p.x ^ (unsigned int)b;
	return q;
}
inline bool
sign(Lit p)
{
	return p.x & 1;
}
inline int
var(Lit p)
{
	return p.x >> 1;
}

// Mapping Literals to and from compact integers suitable for array indexing:
inline int
toInt(Var v)
{
	return v;
}
inline int
toInt(Lit p)
{
	return p.x;
}
inline Lit
toLit(int i)
{
	Lit p;
	p.x = i;
	return p;
}

// const Lit lit_Undef = mkLit(var_Undef, false);  // }- Useful special constants.
// const Lit lit_Error = mkLit(var_Undef, true );  // }

const Lit lit_Undef = { -2 }; // }- Useful special constants.
const Lit lit_Error = { -1 }; // }

//=================================================================================================
// Lifted booleans:
//
// NOTE: this implementation is optimized for the case when comparisons between values are mostly
//       between one variable and one constant. Some care had to be taken to make sure that gcc
//       does enough constant propagation to produce sensible code, and this appears to be somewhat
//       fragile unfortunately.

#define l_True (Glucose::lbool((uint8_t)0)) // gcc does not do constant propagation if these are real constants.
#define l_False (Glucose::lbool((uint8_t)1))
#define l_Undef (Glucose::lbool((uint8_t)2))

class lbool
{
	uint8_t value;

  public:
	explicit lbool(uint8_t v)
		: value(v)
	{
	}

	lbool()
		: value(0)
	{
	}
	explicit lbool(bool x)
		: value(!x)
	{
	}

	bool operator==(lbool b) const { return ((b.value & 2) & (value & 2)) | (!(b.value & 2) & (value == b.value)); }
	bool operator!=(lbool b) const { return !(*this == b); }
	lbool operator^(bool b) const { return lbool((uint8_t)(value ^ (uint8_t)b)); }

	lbool operator&&(lbool b) const
	{
		uint8_t sel = (this->value << 1) | (b.value << 3);
		uint8_t v = (0xF7F755F4 >> sel) & 3;
		return lbool(v);
	}

	lbool operator||(lbool b) const
	{
		uint8_t sel = (this->value << 1) | (b.value << 3);
		uint8_t v = (0xFCFCF400 >> sel) & 3;
		return lbool(v);
	}

	friend int toInt(lbool l);
	friend lbool toLbool(int v);
};
inline int
toInt(lbool l)
{
	return l.value;
}
inline lbool
toLbool(int v)
{
	return lbool((uint8_t)v);
}

//=================================================================================================
// Clause -- a simple class for representing a clause:

class Clause;
typedef RegionAllocator<uint32_t>::Ref CRef;

#define BITS_LBD 13
#define BITS_SIZEWITHOUTSEL 19
#define BITS_REALSIZE 21
class Clause
{
	struct
	{
		unsigned mark : 2;
		unsigned learnt : 1;
		unsigned szWithoutSelectors : BITS_SIZEWITHOUTSEL;
		unsigned canbedel : 1;
		unsigned extra_size : 2; // extra size (end of 32bits) 0..3
		unsigned size : BITS_REALSIZE;
		unsigned seen : 1;
		unsigned reloced : 1;
		unsigned exported : 2; // Values to keep track of the clause status for exportations
		unsigned oneWatched : 1;
		unsigned lbd : BITS_LBD;
	} header;

	union
	{
		Lit lit;
		float act;
		uint32_t abs;
		CRef rel;
	} data[0];

	friend class ClauseAllocator;

	// NOTE: This constructor cannot be used directly (doesn't allocate enough memory).
	template<class V>
	Clause(const V& ps, int _extra_size, bool learnt)
	{
		assert(_extra_size < (1 << 2));
		header.mark = 0;
		header.learnt = learnt;
		header.extra_size = _extra_size;
		header.reloced = 0;
		header.size = ps.size();
		header.lbd = 0;
		header.canbedel = 1;
		header.exported = 0;
		header.oneWatched = 0;
		header.seen = 0;
		for (int i = 0; i < ps.size(); i++)
			data[i].lit = ps[i];

		if (header.extra_size > 0) {
			if (header.learnt)
				data[header.size].act = 0;
			else
				calcAbstraction();
			if (header.extra_size > 1) {
				data[header.size + 1].abs = 0; // learntFrom
			}
		}
	}

  public:
	void calcAbstraction()
	{
		assert(header.extra_size > 0);
		uint32_t abstraction = 0;
		for (int i = 0; i < size(); i++)
			abstraction |= 1 << (var(data[i].lit) & 31);
		data[header.size].abs = abstraction;
	}

	int size() const { return header.size; }
	void shrink(int i)
	{
		assert(i <= size());
		if (header.extra_size > 0) {
			data[header.size - i] = data[header.size];
			if (header.extra_size > 1) { // Special case for imported clauses
				data[header.size - i - 1] = data[header.size - 1];
			}
		}
		header.size -= i;
	}
	void pop() { shrink(1); }
	bool learnt() const { return header.learnt; }
	bool has_extra() const { return header.extra_size > 0; }
	uint32_t mark() const { return header.mark; }
	void mark(uint32_t m) { header.mark = m; }
	const Lit& last() const { return data[header.size - 1].lit; }

	bool reloced() const { return header.reloced; }
	CRef relocation() const { return data[0].rel; }
	void relocate(CRef c)
	{
		header.reloced = 1;
		data[0].rel = c;
	}

	// NOTE: somewhat unsafe to change the clause in-place! Must manually call 'calcAbstraction' afterwards for
	//       subsumption operations to behave correctly.
	Lit& operator[](int i) { return data[i].lit; }
	Lit operator[](int i) const { return data[i].lit; }
	operator const Lit*(void) const { return (Lit*)data; }

	float& activity()
	{
		assert(header.extra_size > 0);
		return data[header.size].act;
	}
	uint32_t abstraction() const
	{
		assert(header.extra_size > 0);
		return data[header.size].abs;
	}

	// Handle imported clauses lazy sharing
	bool wasImported() const { return header.extra_size > 1; }
	uint32_t importedFrom() const
	{
		assert(header.extra_size > 1);
		return data[header.size + 1].abs;
	}
	void setImportedFrom(uint32_t ifrom)
	{
		assert(header.extra_size > 1);
		data[header.size + 1].abs = ifrom;
	}

	Lit subsumes(const Clause& other) const;
	void strengthen(Lit p);
	void setLBD(int i)
	{
		if (i < (1 << (BITS_LBD - 1)))
			header.lbd = i;
		else
			header.lbd = (1 << (BITS_LBD - 1));
	}
	// unsigned int&       lbd    ()              { return header.lbd; }
	unsigned int lbd() const { return header.lbd; }
	void setCanBeDel(bool b) { header.canbedel = b; }
	bool canBeDel() { return header.canbedel; }
	void setSeen(bool b) { header.seen = b; }
	bool getSeen() { return header.seen; }
	void setExported(unsigned int b) { header.exported = b; }
	unsigned int getExported() { return header.exported; }
	void setOneWatched(bool b) { header.oneWatched = b; }
	bool getOneWatched() { return header.oneWatched; }
	void setSizeWithoutSelectors(unsigned int n) { header.szWithoutSelectors = n; }
	unsigned int sizeWithoutSelectors() const { return header.szWithoutSelectors; }
};

//=================================================================================================
// ClauseAllocator -- a simple class for allocating memory for clauses:

const CRef CRef_Undef = RegionAllocator<uint32_t>::Ref_Undef;
class ClauseAllocator : public RegionAllocator<uint32_t>
{
	static int clauseWord32Size(int size, int extra_size)
	{
		return (sizeof(Clause) + (sizeof(Lit) * (size + extra_size))) / sizeof(uint32_t);
	}

  public:
	bool extra_clause_field;

	ClauseAllocator(uint32_t start_cap)
		: RegionAllocator<uint32_t>(start_cap)
		, extra_clause_field(false)
	{
	}
	ClauseAllocator()
		: extra_clause_field(false)
	{
	}

	void moveTo(ClauseAllocator& to)
	{
		to.extra_clause_field = extra_clause_field;
		RegionAllocator<uint32_t>::moveTo(to);
	}

	template<class Lits>
	CRef alloc(const Lits& ps, bool learnt = false, bool imported = false)
	{
		assert(sizeof(Lit) == sizeof(uint32_t));
		assert(sizeof(float) == sizeof(uint32_t));

		bool use_extra = learnt | extra_clause_field;
		int extra_size = imported ? 3 : (use_extra ? 1 : 0);
		CRef cid = RegionAllocator<uint32_t>::alloc(clauseWord32Size(ps.size(), extra_size));
		new (lea(cid)) Clause(ps, extra_size, learnt);

		return cid;
	}

	// Deref, Load Effective Address (LEA), Inverse of LEA (AEL):
	Clause& operator[](Ref r) { return (Clause&)RegionAllocator<uint32_t>::operator[](r); }
	const Clause& operator[](Ref r) const { return (Clause&)RegionAllocator<uint32_t>::operator[](r); }
	Clause* lea(Ref r) { return (Clause*)RegionAllocator<uint32_t>::lea(r); }
	const Clause* lea(Ref r) const { return (Clause*)RegionAllocator<uint32_t>::lea(r); }
	Ref ael(const Clause* t) { return RegionAllocator<uint32_t>::ael((uint32_t*)t); }

	void free(CRef cid)
	{
		Clause& c = operator[](cid);
		RegionAllocator<uint32_t>::free(clauseWord32Size(c.size(), c.has_extra()));
	}

	void reloc(CRef& cr, ClauseAllocator& to)
	{
		Clause& c = operator[](cr);

		if (c.reloced()) {
			cr = c.relocation();
			return;
		}

		cr = to.alloc(c, c.learnt(), c.wasImported());
		c.relocate(cr);

		// Copy extra data-fields:
		// (This could be cleaned-up. Generalize Clause-constructor to be applicable here instead?)
		to[cr].mark(c.mark());
		if (to[cr].learnt()) {
			to[cr].activity() = c.activity();
			to[cr].setLBD(c.lbd());
			to[cr].setExported(c.getExported());
			to[cr].setOneWatched(c.getOneWatched());
			to[cr].setSeen(c.getSeen());
			to[cr].setSizeWithoutSelectors(c.sizeWithoutSelectors());
			to[cr].setCanBeDel(c.canBeDel());
			if (c.wasImported()) {
				to[cr].setImportedFrom(c.importedFrom());
			}
		} else if (to[cr].has_extra())
			to[cr].calcAbstraction();
	}
};

//=================================================================================================
// OccLists -- a class for maintaining occurence lists with lazy deletion:

template<class Idx, class Vec, class Deleted>
class OccLists
{
	vec<Vec> occs;
	vec<char> dirty;
	vec<Idx> dirties;
	Deleted deleted;

  public:
	OccLists(const Deleted& d)
		: deleted(d)
	{
	}

	void init(const Idx& idx)
	{
		occs.growTo(toInt(idx) + 1);
		dirty.growTo(toInt(idx) + 1, 0);
	}
	// Vec&  operator[](const Idx& idx){ return occs[toInt(idx)]; }
	Vec& operator[](const Idx& idx) { return occs[toInt(idx)]; }
	Vec& lookup(const Idx& idx)
	{
		if (dirty[toInt(idx)])
			clean(idx);
		return occs[toInt(idx)];
	}

	void cleanAll();
	void copyTo(OccLists& copy) const
	{
		copy.occs.growTo(occs.size());
		for (int i = 0; i < occs.size(); i++)
			occs[i].memCopyTo(copy.occs[i]);
		dirty.memCopyTo(copy.dirty);
		dirties.memCopyTo(copy.dirties);
	}

	void clean(const Idx& idx);
	void smudge(const Idx& idx)
	{
		if (dirty[toInt(idx)] == 0) {
			dirty[toInt(idx)] = 1;
			dirties.push(idx);
		}
	}

	void clear(bool free = true)
	{
		occs.clear(free);
		dirty.clear(free);
		dirties.clear(free);
	}
};

template<class Idx, class Vec, class Deleted>
void
OccLists<Idx, Vec, Deleted>::cleanAll()
{
	for (int i = 0; i < dirties.size(); i++)
		// Dirties may contain duplicates so check here if a variable is already cleaned:
		if (dirty[toInt(dirties[i])])
			clean(dirties[i]);
	dirties.clear();
}

template<class Idx, class Vec, class Deleted>
void
OccLists<Idx, Vec, Deleted>::clean(const Idx& idx)
{
	Vec& vec = occs[toInt(idx)];
	int i, j;
	for (i = j = 0; i < vec.size(); i++)
		if (!deleted(vec[i]))
			vec[j++] = vec[i];
	vec.shrink(i - j);
	dirty[toInt(idx)] = 0;
}

//=================================================================================================
// CMap -- a class for mapping clauses to values:

template<class T>
class CMap
{
	struct CRefHash
	{
		uint32_t operator()(CRef cr) const { return (uint32_t)cr; }
	};

	typedef Map<CRef, T, CRefHash> HashTable;
	HashTable map;

  public:
	// Size-operations:
	void clear() { map.clear(); }
	int size() const { return map.elems(); }

	// Insert/Remove/Test mapping:
	void insert(CRef cr, const T& t) { map.insert(cr, t); }
	void growTo(CRef cr, const T& t) { map.insert(cr, t); } // NOTE: for compatibility
	void remove(CRef cr) { map.remove(cr); }
	bool has(CRef cr, T& t) { return map.peek(cr, t); }

	// Vector interface (the clause 'c' must already exist):
	const T& operator[](CRef cr) const { return map[cr]; }
	T& operator[](CRef cr) { return map[cr]; }

	// Iteration (not transparent at all at the moment):
	int bucket_count() const { return map.bucket_count(); }
	const vec<typename HashTable::Pair>& bucket(int i) const { return map.bucket(i); }

	// Move contents to other map:
	void moveTo(CMap& other) { map.moveTo(other.map); }

	// TMP debug:
	void debug() { printf(" --- size = %d, bucket_count = %d\n", size(), map.bucket_count()); }
};

/*_________________________________________________________________________________________________
|
|  subsumes : (other : const Clause&)  ->  Lit
|
|  Description:
|       Checks if clause subsumes 'other', and at the same time, if it can be used to simplify 'other'
|       by subsumption resolution.
|
|    Result:
|       lit_Error  - No subsumption or simplification
|       lit_Undef  - Clause subsumes 'other'
|       p          - The literal p can be deleted from 'other'
|________________________________________________________________________________________________@*/
inline Lit
Clause::subsumes(const Clause& other) const
{
	// if (other.size() < size() || (extra.abst & ~other.extra.abst) != 0)
	// if (other.size() < size() || (!learnt() && !other.learnt() && (extra.abst & ~other.extra.abst) != 0))
	assert(!header.learnt);
	assert(!other.header.learnt);
	assert(header.extra_size > 0);
	assert(other.header.extra_size > 0);
	if (other.header.size < header.size || (data[header.size].abs & ~other.data[other.header.size].abs) != 0)
		return lit_Error;

	Lit ret = lit_Undef;
	const Lit* c = (const Lit*)(*this);
	const Lit* d = (const Lit*)other;

	for (unsigned i = 0; i < header.size; i++) {
		// search for c[i] or ~c[i]
		for (unsigned j = 0; j < other.header.size; j++)
			if (c[i] == d[j])
				goto ok;
			else if (ret == lit_Undef && c[i] == ~d[j]) {
				ret = c[i];
				goto ok;
			}

		// did not find it
		return lit_Error;
	ok:;
	}

	return ret;
}

inline void
Clause::strengthen(Lit p)
{
	remove(*this, p);
	calcAbstraction();
}

//=================================================================================================
}

#endif
